An Overlooked Complication, Empyema Necessitatis: An Analysis of 766 Empyema Cases

Introduction: Pleural empyema (PE) is the collection of pus in the pleural cavity. Empyema necessitatis (EN) is a rare complication characterized by the dissemination of pus through the parietal pleura and endothoracic fasia into the surrounding soft tissues and/or skin of the chest wall. It causes complexity in differential diagnosis. The aim of the study was to determine risk factors and share our experience in diagnosis and treatment of empyema necessitatis. Materials and Methods: Seven hundred and sixty-six hospitalized thoracic empyema patients were analyzed retrospectively. The following data was noted; demographic characters (age, sex), comorbidities, side, being of loculated, medical and surgical treatments, the nature of empyema (postoperative, posttraumatic, recurrent), culture results, empyema necessitatis status, morbidities and mortality. SPSSv20.0 program was used for statistical analysis. Results: Empyema necessitatis was seen in 11 (1.4%) patients. Older age and pleural empyema caused by Mycobacterium tuberculosis were determined risk factors for the development of empyema necessitatis. Causative microorganisms yielded significantly higher in culture at EN patients, and major surgical interventions were applied significantly later at them. Sex, comorbidities, EN side, loculation, chest tube insertion, non-tuberculosis microorganisms, the nature of PE, and applied surgery types were not significant factors for the development of EN. Conclusion: Empyema Necessitatis is a rare complication of PE. The most important point is the prevention of its development. EN is more common in advanced age and M. tuberculosis is the most common causing microorganism. Medical and surgical treatment of EN are same with PE. Its misdiagnosis as chest wall soft tissue infection or abscess causes delay in diagnosis and treatment.